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Message-ID: <abee5ee3-ff7c-4849-4831-9591eb07ea63@redhat.com>
Date: Thu, 16 Apr 2020 12:59:14 +0200
From: Auger Eric <eric.auger@...hat.com>
To: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: Lu Baolu <baolu.lu@...ux.intel.com>,
iommu@...ts.linux-foundation.org,
LKML <linux-kernel@...r.kernel.org>,
Joerg Roedel <joro@...tes.org>,
David Woodhouse <dwmw2@...radead.org>,
Jean-Philippe Brucker <jean-philippe@...aro.com>,
Yi Liu <yi.l.liu@...el.com>,
"Tian, Kevin" <kevin.tian@...el.com>,
Raj Ashok <ashok.raj@...el.com>,
Alex Williamson <alex.williamson@...hat.com>,
Christoph Hellwig <hch@...radead.org>,
Jonathan Cameron <jic23@...nel.org>
Subject: Re: [PATCH v11 07/10] iommu/vt-d: Add svm/sva invalidate function
Hi Jacob,
On 4/10/20 11:56 PM, Jacob Pan wrote:
> On Thu, 9 Apr 2020 10:50:34 +0200
> Auger Eric <eric.auger@...hat.com> wrote:
>
>> Hi Jacob,
>>
>> On 4/3/20 8:42 PM, Jacob Pan wrote:
>>> When Shared Virtual Address (SVA) is enabled for a guest OS via
>>> vIOMMU, we need to provide invalidation support at IOMMU API and
>>> driver level. This patch adds Intel VT-d specific function to
>>> implement iommu passdown invalidate API for shared virtual address.
>>>
>>> The use case is for supporting caching structure invalidation
>>> of assigned SVM capable devices. Emulated IOMMU exposes queue
>>> invalidation capability and passes down all descriptors from the
>>> guest to the physical IOMMU.
>>>
>>> The assumption is that guest to host device ID mapping should be
>>> resolved prior to calling IOMMU driver. Based on the device handle,
>>> host IOMMU driver can replace certain fields before submit to the
>>> invalidation queue.
>>>
>>> ---
>>> v11 - Removed 2D map array, use -EINVAL in granularity lookup array.
>>> Fixed devTLB invalidation granularity mapping. Disregard G=1
>>> case and use address selective invalidation only.
>>>
>>> v7 review fixed in v10
>>> ---
>>>
>>> Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
>>> Signed-off-by: Ashok Raj <ashok.raj@...el.com>
>>> Signed-off-by: Liu, Yi L <yi.l.liu@...el.com>
>>> ---
>>> drivers/iommu/intel-iommu.c | 158
>>> ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 158
>>> insertions(+)
>>>
>>> diff --git a/drivers/iommu/intel-iommu.c
>>> b/drivers/iommu/intel-iommu.c index 94c7993dac6a..045c5c08d71d
>>> 100644 --- a/drivers/iommu/intel-iommu.c
>>> +++ b/drivers/iommu/intel-iommu.c
>>> @@ -5594,6 +5594,163 @@ static void
>>> intel_iommu_aux_detach_device(struct iommu_domain *domain,
>>> aux_domain_remove_dev(to_dmar_domain(domain), dev); }
>>>
>>> +/*
>>> + * 2D array for converting and sanitizing IOMMU generic TLB
>>> granularity to
>>> + * VT-d granularity. Invalidation is typically included in the
>>> unmap operation
>>> + * as a result of DMA or VFIO unmap. However, for assigned devices
>>> guest
>>> + * owns the first level page tables. Invalidations of translation
>>> caches in the
>>> + * guest are trapped and passed down to the host.
>>> + *
>>> + * vIOMMU in the guest will only expose first level page tables,
>>> therefore
>>> + * we do not support IOTLB granularity for request without PASID
>>> (second level).
>>> + *
>>> + * For example, to find the VT-d granularity encoding for IOTLB
>>> + * type and page selective granularity within PASID:
>>> + * X: indexed by iommu cache type
>>> + * Y: indexed by enum iommu_inv_granularity
>>> + * [IOMMU_CACHE_INV_TYPE_IOTLB][IOMMU_INV_GRANU_ADDR]
>>> + */
>>> +
>>> +const static int
>>> inv_type_granu_table[IOMMU_CACHE_INV_TYPE_NR][IOMMU_INV_GRANU_NR] =
>>> {
>>> + /*
>>> + * PASID based IOTLB invalidation: PASID selective (per
>>> PASID),
>>> + * page selective (address granularity)
>>> + */
>>> + {-EINVAL, QI_GRAN_NONG_PASID, QI_GRAN_PSI_PASID},
>>> + /* PASID based dev TLBs */
>>> + {-EINVAL, -EINVAL, QI_DEV_IOTLB_GRAN_PASID_SEL},
>>> + /* PASID cache */
>>> + {-EINVAL, -EINVAL, -EINVAL}
>>> +};
>>> +
>>> +static inline int to_vtd_granularity(int type, int granu)
>>> +{
>>> + return inv_type_granu_table[type][granu];
>>> +}
>>> +
>>> +static inline u64 to_vtd_size(u64 granu_size, u64 nr_granules)
>>> +{
>>> + u64 nr_pages = (granu_size * nr_granules) >>
>>> VTD_PAGE_SHIFT; +
>>> + /* VT-d size is encoded as 2^size of 4K pages, 0 for 4k, 9
>>> for 2MB, etc.
>>> + * IOMMU cache invalidate API passes granu_size in bytes,
>>> and number of
>>> + * granu size in contiguous memory.
>>> + */
>>> + return order_base_2(nr_pages);
>>> +}
>>> +
>>> +#ifdef CONFIG_INTEL_IOMMU_SVM
>>> +static int intel_iommu_sva_invalidate(struct iommu_domain *domain,
>>> + struct device *dev, struct
>>> iommu_cache_invalidate_info *inv_info) +{
>>> + struct dmar_domain *dmar_domain = to_dmar_domain(domain);
>>> + struct device_domain_info *info;
>>> + struct intel_iommu *iommu;
>>> + unsigned long flags;
>>> + int cache_type;
>>> + u8 bus, devfn;
>>> + u16 did, sid;
>>> + int ret = 0;
>>> + u64 size = 0;
>>> +
>>> + if (!inv_info || !dmar_domain ||
>>> + inv_info->version !=
>>> IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
>>> + return -EINVAL;
>>> +
>>> + if (!dev || !dev_is_pci(dev))
>>> + return -ENODEV;
>>
>> Check (domain->flags & DOMAIN_FLAG_NESTING_MODE)?
> Good point
>
>>> +
>>> + iommu = device_to_iommu(dev, &bus, &devfn);
>>> + if (!iommu)
>>> + return -ENODEV;
>>> +
>>> + spin_lock_irqsave(&device_domain_lock, flags);
>>> + spin_lock(&iommu->lock);
>>> + info = iommu_support_dev_iotlb(dmar_domain, iommu, bus,
>>> devfn);
>>> + if (!info) {
>>> + ret = -EINVAL;
>>> + goto out_unlock;
>>> + }
>>> + did = dmar_domain->iommu_did[iommu->seq_id];
>>> + sid = PCI_DEVID(bus, devfn);
>>> +
>>> + /* Size is only valid in non-PASID selective invalidation
>>> */
>>> + if (inv_info->granularity != IOMMU_INV_GRANU_PASID)
>>> + size =
>>> to_vtd_size(inv_info->addr_info.granule_size,
>>> +
>>> inv_info->addr_info.nb_granules); +
>>> + for_each_set_bit(cache_type, (unsigned long
>>> *)&inv_info->cache, IOMMU_CACHE_INV_TYPE_NR) {
>>> + int granu = 0;
>>> + u64 pasid = 0;
>>> +
>>> + granu = to_vtd_granularity(cache_type,
>>> inv_info->granularity);
>>> + if (granu == -EINVAL) {
>>> + pr_err("Invalid cache type and granu
>>> combination %d/%d\n", cache_type,
>>> + inv_info->granularity);
>> rate unlimited traces here and after.
still to be fixed
>> ret = -EINVAL?
>> also related to the discussion we had on the VFIO series. What is the
>> error policy?
> Invalidation should not fail, there is no way to tell the guest. this
> can be a void function or VFIO can ignore it similar to what is done to
> iommu_unmap.
OK it was just for reminder
>
>
>>> + break;
>>> + }
>>> +
>>> + /* PASID is stored in different locations based on
>>> granularity */
>> not sure the above comment really is requested
> Just to explain the situation where PASID can be in pasid_info or
> addr_info.
>
>>> + if (inv_info->granularity == IOMMU_INV_GRANU_PASID
>>> &&
>>> + inv_info->pasid_info.flags &
>>> IOMMU_INV_PASID_FLAGS_PASID)
>>> + pasid = inv_info->pasid_info.pasid;
>>> + else if (inv_info->granularity ==
>>> IOMMU_INV_GRANU_ADDR &&
>>> + inv_info->addr_info.flags &
>>> IOMMU_INV_ADDR_FLAGS_PASID)
>>> + pasid = inv_info->addr_info.pasid;
>>> +
>>> + switch (BIT(cache_type)) {
>>> + case IOMMU_CACHE_INV_TYPE_IOTLB:
>>> + if ((inv_info->granularity ==
>>> IOMMU_INV_GRANU_ADDR) &&
>>> + size && (inv_info->addr_info.addr
>>> & ((BIT(VTD_PAGE_SHIFT + size)) - 1))) {
>>> + pr_err("Address out of range,
>>> 0x%llx, size order %llu\n",
>>> + inv_info->addr_info.addr,
>>> size);
>>> + ret = -ERANGE;
>>> + goto out_unlock;
>>> + }
>>> +
>>> + qi_flush_piotlb(iommu, did,
>>> + pasid,
>>> +
>>> mm_to_dma_pfn(inv_info->addr_info.addr),
>> This does not sound correct to me:
>> inv_info->addr_info.addr and inv_info->addr_info.flags are not valid
>> in case of PASID-selective invalidation
> If granu is PASID-selective, this address is ignored. Since npages = -1.
Ah OK. Maybe add a comment since it is a bit strange to see irrelevant
fields to be called in PASID-selective case.
Thanks
Eric
>
>>> + (granu ==
>>> QI_GRAN_NONG_PASID) ? -1 : 1 << size,
>>> + inv_info->addr_info.flags
>>> & IOMMU_INV_ADDR_FLAGS_LEAF); +
>>> + /*
>>> + * Always flush device IOTLB if ATS is
>>> enabled. vIOMMU
>>> + * in the guest may assume IOTLB flush is
>>> inclusive,
>>> + * which is more efficient.
>>> + */
>>> + if (info->ats_enabled)
>>> + qi_flush_dev_iotlb_pasid(iommu,
>>> sid, info->pfsid,
>>> + pasid,
>>> info->ats_qdep,
>>> +
>>> inv_info->addr_info.addr, size,
>> same
>>> + granu);
>>> + break;
>>> + case IOMMU_CACHE_INV_TYPE_DEV_IOTLB:
>>> + if (info->ats_enabled)
>>> + qi_flush_dev_iotlb_pasid(iommu,
>>> sid, info->pfsid,
>>> +
>>> inv_info->addr_info.pasid, info->ats_qdep,
>> nit: use pasid directly
> will do.
>
>>> +
>>> inv_info->addr_info.addr, size,
>>> + granu);
>>> + else
>>> + pr_warn("Passdown device IOTLB
>>> flush w/o ATS!\n");
>>> + break;
>>> + case IOMMU_CACHE_INV_TYPE_PASID:
>>> + qi_flush_pasid_cache(iommu, did, granu,
>>> inv_info->pasid_info.pasid);
>>> + break;
>>> + default:
>>> + dev_err(dev, "Unsupported IOMMU
>>> invalidation type %d\n",
>>> + cache_type);
>>> + ret = -EINVAL;
>>> + }
>>> + }
>>> +out_unlock:
>>> + spin_unlock(&iommu->lock);
>>> + spin_unlock_irqrestore(&device_domain_lock, flags);
>>> +
>>> + return ret;
>>> +}
>>> +#endif
>>> +
>>> static int intel_iommu_map(struct iommu_domain *domain,
>>> unsigned long iova, phys_addr_t hpa,
>>> size_t size, int iommu_prot, gfp_t gfp)
>>> @@ -6179,6 +6336,7 @@ const struct iommu_ops intel_iommu_ops = {
>>> .is_attach_deferred =
>>> intel_iommu_is_attach_deferred, .pgsize_bitmap =
>>> INTEL_IOMMU_PGSIZES, #ifdef CONFIG_INTEL_IOMMU_SVM
>>> + .cache_invalidate = intel_iommu_sva_invalidate,
>>> .sva_bind_gpasid = intel_svm_bind_gpasid,
>>> .sva_unbind_gpasid = intel_svm_unbind_gpasid,
>>> #endif
>>>
>> Thanks
>>
>> Eric
>>
>
> [Jacob Pan]
>
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